The present invention relates to a conical-bottom silo which is particularly, albeit not solely, suitable for small-sized pieces of plastic material and rubber with characteristics of high elasticity, as in the case of plastics of the "stretch" type (LLPE, linear, low, polyethylene).
Silos for small-sized pieces of plastic material are already known, such as the silo described in the U.S. Pat. No. 4,185,925. This patent relates to a conical-bottom silo with a conical screw stirrer inserted axially in the conical bottom of the silo and a cylindrical screw delivery and outlet part situated at an outlet port arranged laterally in relation to the stirrer at the lower end of the conical bottom of the silo.
A silo of this type functions perfectly for the various kinds of small-sized pieces of plastic material except in the case wherein particularly elastic plastics and rubber are being dealt with. With a material having these properties, areas of compression can in fact form in the conical bottom of the silo due to the action performed by the stirrer. Blocks of materials, which prevent the conical screw and the relative motor from moving, are then created in these areas. As a result thereof, there is discontinuity of operations and feeding (metering) of the material during delivery and strong mechanical stress of the screw with subsequent damage thereto and possible breakage of the motor.